Centrifugal fan or centrifugal pump for two directions of rotation



g- 15, 1950 J. OVERWEG CENTRIFUGAL FAN 0R CENTRIFUGAL PUMP FOR TWO DIRECTIONS 0F ROTATION Flled July 9, 1946 FIGS Patented Aug 15; 1950 'CEN'EEJIFUGAL FAN R CEN'IRIFUGAL PUMP V i DIREiJTiONS'OF EQTA'EION Johannes fiverweg, liiengelo' Netherlands, Jassignoiito Machinefabriek Gebr. Stork & 00. N. V., ir'iengelo, Netherlands, a company of the Netherlands Application-311MB,1946, s s-awakened i In theNetherlands August 16, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires August 16, 1964 3 Claims. 1 This invention relates to a centrifugal fan or a centrifugal pump for two directions of rotation and provided with a guide apparatus having two sets of guide blades and being axially adjustable between the circumference of the impeller and the flow channel in the casing in such a manner that for the one direction of rotation the one set of blades and for the opposite direction of rotation the other set of blades is active.

Centrifugal fans of this kind are known the spiral casing of which has two flow channels which are arranged side by side in axial direction,

one of them serving for ahead running and the I remove said drawback and to this end the sets of guide blades are arranged in such a manner that on adjustment they are adapted to occupy the position of each other both at the inlet and the outlet of the blades, whereby the casing is provided with a common flow channel for both directions or rotation.

Further features of the invention will appear from the following description with reference to the accompanying drawing, Fig. 1 of which shows a longitudinal section of part of a centrifugal fan according to the invention.

Fig. 2 is a cross section of the fan on a smaller scale and taken of line II-II of Fig. 1, the guide apparatus being drawn in full lines in the position for a direction of rotation corresponding to the arrow.

Fig. 3 is a cross section similar to that of Fig. 2 of a centrifugal fan according to a modified embodiment.

The impeller which is denoted by the reference numeral I has blades 2 and is keyed to shaft 3. The impeller is enclosed by a casing 4 which at its circumference forms a flow channel 5 for the fluid.

Between the flow channel 5 and the impeller I a guide apparatus 6 is arranged which is provided with two sets of guide blades 1, 8, one set of which serving for the one direction of rotation and the second set for the other direction of rotation. The axial adjustment of the guide apparatus may be obtained by some adjusting cylinders 9 placed at a convenient angular distance and operating e. g. with compressed air.

With the embodiment shown in Fig. 2 the flow channel 5 is bounded by a circumferential wall formed by two spirals which at it! are joined to the periphery of the guide apparatus and thus each extends across about 180.

When the impeller should rotate opposite to the direction of the arrow indicated in Figs. 2 and 3 the guide apparatus 6 is adjusted in such a manner that the blades 8 are active which are shown in dotted lines in Figs. 2 and 3.

With the embodiment according to Fig. 3 the flow channel 5 is bounded by a circle-shaped circumferential wall which is eccentric to the impeller I. The guide blades 1, 8 of both sets are of equal form and their outlet end is radially directed. As with this arrangement the guide blades discharge the fluid substantially in radial direction into the casing the velocity of discharge in the flow channel 5 will be very small so that the circumferential wall of this channel may also be placed concentric to the guide apparatus.

It should be noted that the invention is not limited to the use of a pneumatically adjustable guide apparatus as the adjustment may also be obtained manually or by electric means.

What I claim is:

1. A centrifugal fan or a centrifugal pump for two directions of rotation and provided with a guide apparatus having two sets of guide blades, which are axially adjustable between the circumference of the impeller and the flow channel in the casing and are so arranged that on adjustment they are adapted to occupy the position of each other both at the inlet and the outlet of the blades in such a manner that for the one direction of rotation the one set of blades and for the opposite direction of rotation the other set of blades is active, the casing being provided with a common flow channel for both directions of rotation, said channel being bounded by a spiral-shaped wall, joined to the periphery of the guide apparatus opposite the outlet of the flow channel and from this point the flow channel being widened on either side.

2. A reversible centrifugal fan or centrifugal pump having an axially displaceable guide apparatus with a set of guide blades for each direction of rotation inserted between the periphery of the impeller wheel and a receiving channel in the housing operative in both directions of rotation and consisting of two parts, each of which is formed as a diffusor and commences at a point of the periphery substantially diametrically opposite the exhaust and each extending along half of the periphery, the guide vanes of each set being difierently curved so as to deflect the medium from the entrance angle to a outlet direction common to both sets of guide blades and directed towards the discharge end of the corresponding part of the receiving channel.

3. A centrifugal fan or centrifugal pump for two directions of rotation having an axially displaceable guide apparatus with a set of guide blades for each direction of rotation inserted between the periphery of the impeller wheel and a receiving channel in the housing operative in both directions of rotation and comprising two 15 5 vanes of each set being differently curved.

J OHANNES OVERW'EG.

REFERENCES CITED The following references are of record in the 0 file of this patent:

FOREIGN PATENTS Number Country Date 451,806 Denmark Apr. 21, 1927 305,214 Great Britain Jan. 29, 1929 

